Medically reviewed by Kristin Hall, FNP
Written by Our Editorial Team
Last updated 12/01/2020
The sweat that pools under your breasts on a hot day is one kind of discomfort, but developing a rash there takes things to a whole new level.
Having a rash in the skin folds under your breasts can be maddening, particularly if you have large breasts that keep the itchy, inflamed skin from ever truly drying out.
Scratching or drying the affected area isn’t always something that can be done conspicuously, so an under-breast rash can make you want to stay at home where you can at least suffer in peace.
Under breast rashes are not uncommon, and there are many possible culprits. Understanding what’s causing your skin rash is the first step in making it go away for good.
Think of it as diaper rash under your breasts — intertrigo occurs in places where skin rubs against or folds over itself, creating ripe conditions for moisture and friction. And the warmth in those creases only serves to make things worse.
Intertrigo results in a red, inflamed, burning or painful rash. There may be scaling or small pimple-like sores associated with intertrigo. It may also begin to smell funny.
Secondary infections are a risk with intertrigo, as well. It could even develop into a bacterial or yeast infection. Strep and erythrasma bacterial strains or a candida yeast can infect the rash and make your discomfort worse.
Intertrigo is treatable, even with a secondary diagnosis. Keeping the area dry will help prevent this condition, but barrier medications like zinc oxide will help treat it. If it’s coupled with a bacterial infection, you’ll need to get a topical or oral antibiotic from a healthcare professional, and if it’s paired with a fungal infection, your healthcare provider can prescribe a topical or oral antifungal treatment.
Despite the name, ringworm (tinea) isn’t caused by a worm, but a fungus. It generally causes a circular rash, in the shape of a ring, with a raised, potentially scaly border. Ringworm can be found on various parts of the body including the feet (athlete’s foot), the groin (jock itch), and under your breasts.
Because it’s a fungal infection, ringworm thrives in warm, damp places, and the area under your breasts is a perfect home for it. The rash can be extremely itchy and irritating. Left untreated it can spread to other areas of your body and even to other people — it’s very contagious.
Depending on the seriousness of your rash, you may be able to treat it with over-the-counter antifungal medications. You can find these in drug stores under names like clotrimazole and miconazole.
However, if your rash doesn’t improve or if the symptoms are unbearable, it is important to reach out to your healthcare provider for an evaluation and treatment plan.
Hives, also known as urticaria, affects one in five people at least sometime during their lives. They are generally red or flesh colored bumps that may resemble bug bites. When you press them, the center of a red hive will turn white, called “blanching.”
One notable characteristic of hives is their itch — it can be severe and relentless. Hives may appear and disappear quickly.
Hives can be caused by a number of factors including: allergens like foods, pet dander, latex or pollen; medications; insect stings or bites; infections, such as urinary tract infections or strep throat; and viral infections such as the common cold. Alcohol, exercise, and stress can worsen hives.
Treating hives generally involves avoiding the thing that triggered them while treating the current itch. Over-the-counter antihistamines can block the effects of the allergen that’s causing your breakouts, or stop the allergic reaction.
However, if your reaction is severe and hives are accompanied with the swelling of your lips or tongue, or difficulty breathing, you may be suffering a medical emergency and need to call 911.
Like several other possible under-breast rashes, cellulitis can thrive in the dark, warm, moist areas of the body because these conditions are ripe for bacteria. Cellulitis will make your skin red and inflamed, but even before the “rash” appears, you may feel ill, with chills, fever and fatigue. In severe cases, you may develop blisters or open sores.
Cellulitis requires a healthcare provider's treatment, as you’ll need prescription antibiotics to kill the bacterial infection. If you have abscesses or blisters, they need to be evaluated by a healthcare provider immediately.
Preventing cellulitis involves keeping the area under your breasts clean and dry. Avoiding lotions and other topical products can also help.
Chickenpox isn’t only a childhood disease, and while it’s less common now than it was decades ago (before the vaccine was available), it’s still a possible cause of under breast skin irritation.
If your rash is caused by chickenpox, it’s likely not limited to the area under your breasts, as it typically results in blisters on the chest, back and face, and it spreads across the entire body.
Chickenpox blisters are extremely itchy. The illness is a virus, so antibiotics won’t help and you might experience fever, fatigue, loss of appetite, and a headache one or two days before the rash develops.
However, if you believe you may have chickenpox, you should contact a healthcare provider as complications can arise.
Related to chickenpox, shingles are more common in older adults. The same virus that causes chickenpox lives dormant in your body for years and can reactivate in the form of shingles.
Shingles causes fluid-filled blisters, burning or tingling skin, feeling sick, and pain. Typically, the rash begins around one side of your waist or back, and does not spread to other areas.
If you believe you have shingles, talk with a healthcare professional immediately about potential treatment options.
Antiviral drugs can limit pain and the duration of your suffering, but they work best if taken within the first 72 hours of developing the rash. .
If you’ve received the standard course of vaccines, it’s unlikely you have measles. However, measles cases are on the rise, and it is a contagious virus.
A rash is just one symptom of measles. The rash typically appears a few weeks after your exposure to the measles virus, and it typically spreads from your head down to your trunk, including underneath your breasts.
Additional symptoms are similar to those experienced with the common cold -- cough, runny nose, fever, and eye irritation.
If you suspect you have measles, contact a healthcare professional for treatment advice. Generally, measles treatment involves managing your symptoms and preventing complications.
We know — no one is excited for boob sweat. And while it’s only a minor inconvenience most of the time, sometimes that sweat under your breast can turn into a rash under your breast.
There are plenty of reasons you might develop a rash under your breasts — from fungal and bacterial infections, to certain allergic reactions or even certain viral infections.
Luckily, if you’re experiencing a rash under your breasts, like other skin rashes, it’s usually treatable, either with antibiotics, topical medications or even some good old-fashioned time and cleanliness.
Although a rash under your breast isn’t the most common thing out there, it can happen to anyone and everyone. So, if you’re struggling with one and you’re embarrassed about reaching out to your healthcare provider for assistance, don’t be — they’re here to help, just like we are.